BackgroundIn order to choose the appropriate implant size and to prevent complications, an oral surgeon must know the size and shape of the mandible. In the posterior mandibular region, a lingual undercut is often found and could represent a difficulty hard to manage if a lingual or buccal perforation occur. A large series of computed tomography (CT) images of the mandibular first molar was evaluated and the bone morphology, the prevalence and the degree of the lingual concavity in the first molar region were studied.Material and MethodsOne hundred and fifty-one computed tomography (CT) examinations of patients were retrospectively evaluated to determine anatomical variations in bone morphology in the submandibular fossa region.ResultsA total of 151 subjects were included, consisting of 64 males (M) (42.4%) and 87 females (F) (57.6%). The under-cut type ridge was present in 64.2% of the cases. The concavity angle was 66.6 ± 8.9° (M) and 71.6 ± 8.4° (F) and the linear concavity depth 4.5 ± 2.3 mm (M) and 3.1 ± 1.7 mm (F) (p>0.05).ConclusionsMandibles with any lingual concavity present a potential increased risk of lingual cortical perforation during implant placement surgery. CT imaging allows characterizing the anatomy of the submandibular fossa and provides other important information for the preoperative assessment of the posterior mandible for dental implants placement. Key words:Anatomy, computed tomography, dental implants, intraoperative complications, mandible, panoramic radiography, radiographic examination.

BackgroundThe objective of this study was to evaluate the association between the presence of mandibular third molars and the occurrence of carious lesions in the distal aspect of the mandibular second molar.Material and MethodsA retrospective cohort study comprising 327 lower third molars extracted in the Oral Surgery and Implantology Master’s Degree program of the School of Dentistry of the University of Barcelona (Barcelona, Spain) was carried out. A descriptive and bivariate analysis was made. The diagnosis of caries in the second molar and the position of the mandibular third molar were evaluated through panoramic radiographies.ResultsThe sample included 203 patients, 94 males (46.3%) and 109 females (53.7%), with a mean age of 26,8 years and 327 lower third molars. The prevalence of second molar distal caries was 25.4% (95% CI= 20.6% to 30.2%). This pathology was significantly more frequent when the third molar was in a horizontal position (27.7%), when the contact point was at (45,8%) or below (47.0%) the cementoenamel junction (CEJ), and when the distal CEJ of the mandibular second molar and the mesial CEJ of the third molar was 7 to 12 mm apart.ConclusionsHorizontal lower third molars with contact points at or below the CEJ are more likely to produce distal caries in the mandibular second molars. Due to the high prevalence of this pathology (20.6% to 30.2%), a prophylactic removal of lower third molars with the above-mentioned features might be advisable. Key words:Second molar, caries, third molar, prophylactic removal.

Objectives: The aim of this study is to compare the analgesic and anti-inflammatory effects of the local postoperative administration of a single 12-mg dose of betamethasone after the surgical removal of impacted lower third molars. Study Design: A split-mouth, triple-blind, randomized, placebo-controlled clinical trial of 25 patients requiring the surgical removal of symmetrical lower third molars was performed. In the experimental side, a 12-mg dose of betamethasone was administered submucosally after the surgical procedure, while in the control side a placebo (sterile saline solution) was injected in the same area. To assess postoperative pain, visual analogue scales and the consumption of rescue analgesic were used. The facial swelling and trismus were evaluated by measuring facial reference distances and maximum mouth opening. Results: There were no significant differences between the two study groups regarding postoperative pain, facial swelling and trismus. Conclusions: The injection of a single dose of betamethasone does not seem to reduce pain, facial swelling and trismus after impacted lower third molar removal when compared to placebo. Key words:Third molar extraction, corticosteroids, betamethasone.

1. The objective was to evaluate the occurrence of cultivable components of the Bacteroides fragilis group in faeces of broiler chickens and their antimicrobial susceptibility patterns. 2. Faecal samples of 36 × 45-d-old Cobb broilers of both sexes from 15 different flocks on one farm were diluted 10-fold and plated on to Bacteroides-bile-esculin agar for colony count and isolation. Identification was by molecular methods and antimicrobial susceptibility in the agar dilution assay. 3. A total of 236 isolates was recovered from a mean population of 3·32 × 10(7 )colony-forming units/g of faeces. B. fragilis was shown to be the predominant Bacteroides species (45·3%), followed by B. distasonis (35·6%), B. vulgatus (8·9%), B. ovatus (2·5%) and B. stercoris (1·3%). 4. Among 204 bacterial isolates tested, high resistance to ampicillin (98·5%), norfloxacin (95·1%) and tetracycline (88·2%) were observed. High (89·7%) multi-drug resistance was observed to 3-7 of the tested drugs. 5. Components of the B. fragilis group were sub-dominant in broiler faecal microbiota, with a different species pattern compared with human and high antimicrobial multi-drug resistance.

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